Powered folding mechanism

ABSTRACT

A powered folding mechanism includes a locking pin for normally retaining a blade of a rotary wing aircraft in an extended position relative to a blade grip and a cam for rotation in one direction to first withdraw the locking pin and then fold the blade and for rotation in the opposite direction to first return the blade to the extended position and then re-engage the locking pin. Two embodiments of the powdered folding mechanism are disclosed, one of which operates directly on the blade and the other of which operates by means of a drag link connected between the grip and the blade.

United States Patent Covington et 1451 July 31, 1973 [5 POWERED FOLDING MECHANISM 3,612,444 10/1971 Girand 416/143 [75] Inventors: Cecil Covington, Hurst; Joe D. FOREIGN PATENTS OR APPLICATIONS Puckett, Smithfield, both of 852,841 11/1960 Great Britain 416/143 :Tt I.,FrtWrth,T. a [73] Asslgnee ex mu m o 0 ex Primary ExaminerEverette A. Powell, Jr. Filedi Jlllle 1971 Attorney-Richards, Harris & Hubbard [21] Appl. N0.: 148,824

[57] ABSTRACT A powered folding mechanism includes a locking pin [2%] for normally retaining a blade of a rotary g aircraft "5 142 in an extended position relative to a blade grip and a 1 1e 0 cam for rotation in one direction to first withdraw the locking pin and then fold the blade and for rotation in [56] Reierences Clted the opposite direction to first return the blade to the ex- UNITED STATES PATENTS tended position and then re-engage the locking pin. 2,815,820 12/1957 Papadakos 416/143 Two embodiments of the powdered folding mechanism 3,153,455 10/1964 Mosinskis 416/143 X are disclosed, one of which operates directly on the g f i i blade and the other of which operates by means of a 0s1ns 1s 3,356,155 12/1967 Ferris 416/143 drag lmk connected between the gnp and the blade 3,438,447 4/1969 Ferris 416/143 9 Claims, 9 Drawing Figures 32 26 34 TE 9 1 1 ill 1s I 1 I2 58 2 2O 38 4 \v I 28 4o lll' 6O I so I. o 54 30 W 58 62 PMENHJJ 3. 749.51 5

sum 1 0r 4 INVENTOR CECIL E. COVINGTON JOE D. PUCKETT ATTORNEYS PAIENIEUJULS 1 ms 5 5 SHEET 2 [1F 4 INVENTOR CECIL E. COVINGTON JOE D. PUCKETT ATTORNEYS PAIENHLJIH '11 IHH SHEET 3 UF 4 V (D '0 O 0 Q J N v Q 9 a. u s 1 INVENTOR i N CECIL E. COVINGTON JOE D. PUCKETT ATTORNEYS PATENIED JUL 3 I ma SHEET b 0F 4 FIG.9

INVENTOR CECIL E. COVINGTON JOE D. PUCKETT ATTORNEYS POWERED FOLDING MECHANISM BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a powered folding mechanism, and more particularly to apparatus for folding the blades of rotary wing aircraft.

Most helicopters and other rotary wing aircraft are equipped with blades that do not fold, i.e., no provision is made for pivoting the blades relative to the blade grips of the aircraft. There are, however, certain circumstances in which folding blades are desirable. For example, in helicopters adapted for use on aircraft carriers, folding blades are advantageous in conserving space on hanger decks, etc. Conversely, it is advantageous to fold the blades of a convertiplane during horizontal flight in order to reduce drag.

The present invention comprises a novel powered folding mechanism which is especially useful in folding the blades of rotary wing aircraft. In accordance with the preferred embodiment of the invention, a first member is supported on a second member for pivotal movement between extended and folded positions. A locking member is supported on one of the members and is normally received by structure on the other member to retain the second member in the extended position. A camming member is mounted for movement in one direction to first disengage the locking member and then pivot the second member from the extended position to the folded position. Upon subsequent movement in the opposite direction, the camming member first pivots the second member from the folded position to the extended position and then engages the locking member with the receiving structure.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein:

FIG. 1 is a perspective view of a powered folding mechanism comprising a first embodiment of the invention in which certain parts have been broken away more clearly to illustrate certain features of the invention;

FIGS. 2, 3, 4, and 5 are illustrations of progressive steps in the operation of the powered folding mecha nism shown in FIG. 1;

FIG. 6 is a top view of a powered folding mechanism comprising a second embodiment of the invention; and

FIGS. 7, 8, and 9 and illustrations of progressive steps in the operation of the powered folding mechanism shown in FIG. 6.

DETAILED DESCRIPTION Referring now to the Drawings, and particularly to FIG. 1, there is shown a powered folding mechanism 10 comprising a first embodiment of the present invention. The mechanism 10 includes a blade grip 12 of a rotary wing aircraft such as a helicopter, a convertiplane, or the like. The grip 12 is supported on a hub for rotation about the axis of a mast and includes a pair of pitch change plates 14 which are manipulated by conventional apparatus to effect collective and cyclic pitch control. The plates 14 support a pair of bearings 16 (only one of which is shown) that in turn support a pin 18. A pair of bearings 20 (only one of which is'shown) are mounted on the pin 18 and support a fitting 22. A blade 24 is secured to the fitting 22 by means of a plurality of fasteners 26. Thus, it will be understood that the inboard end of the blade 24 is supported on the outboard end of the grip 12, and that the blade is mounted for rotation relaive to the grip about the axis of the pin 18. 1

A locking pin 28 is slidably supported in the fitting 22 for movement between the locking position shown in FIG. 1 and a retracted unlocking position. A pin receiving member 30 is supported between the plates 14. The locking pin 28 is normally received in the pin receiving member 30 to prevent rotation of the blade 24 relative to the grip 12 of the aircraft.

A rotary actuator 32 is supported on the upper plate 14. The rotary actuator 32 comprises a conventional 28 Volt DC electric motor rated at about 1 inch pound output torque at 6 amperes. The motor drives a planetary speed reducer 34 having a ratio of about 16,000: I. The output of the speed reducer 34 is in turn connected to the pin 18. The rotary actuator 32 further includes an electrically actuated brake and a slip clutch to prevent excessive torque loads.

A cam 36 is coupled to the pin 18 by a spline connection 38. Thus, upon operation of the rotary actuator 32, both the pin 18 and the cam 36 rotate relative to the plates 14. The cam 36 is coupled to the locking pin 28 by a pin 40 and a camming slot 42. The slot 42 extends in such a direction that upon rotation of the cam 36 in the direction indicated by the arrow 44, the locking pin 28 is disengaged from the pin receiving member 30.

Upon further rotation in the direction indicated by the arrow 44, the cam 36 engages a stop 46 on the fitting 22. Thereafter, rotation of the cam 36 under the action of the rotary actuator 32 causes pivotal movement of the blade 24 about the axis of the pin 18.

Coincidentally with the engagement of the cam 36 with the stop 46, a surface 48 on the cam 36 becomes aligned with a pawl 50. The pawl 50 is supported on the fitting 22 by a pin 52 and includes a cam follower receiving portion 54. A pair of cam followers 56 are slidably supported on the fitting 22 on opposite sides of the pawl 50. The cam followers 56 are mounted for engagement with a pair of cams 58 that are supported on the plates 14 of the grip 12.

The location of the earns 58 is such that the cam followers 56 engage the earns 58 in response to pivotal movement of the blade 24 out of the extended position shown in FIG. 1 under the action of the rotary actuator 32. Upon engagement with the earns 58, the cam followers 56 are driven inwardly, i.e., toward the pawl 50. The cam follwers 56 and the cam follower receiving portion 54 of the pawl 50 are provided with facing surfaces 60 and 62, respectively, which cooperate to drive the pawl 50 toward the cam 36 in response to inward movement of the cam followers 56. Thus, the earns 58 of the cam followers 56, and the cam follower receiving portion 54 of the pawl 50 function to lock the pawl 50 in engagement with the surface 48 of the cam 36 whenever the blade 24 is displaced from the extended position shown in FIG. I.

The operation of the powered folding mechanism 10 will be better understood by referring to FIGS. 2, 3, 4 and 5. Referring particularly to FIG. 2, the blade 24 is initially extended for flight, i.e., the blade 24 initially extends parallel to the grip 12. When the blade 24 is in the extended position, the locking pin 28 is received in the pin receiving member 30 to prevent rotation of the blade relative to the grip 12. 7

Whenever it is desired to fold the blade 24, the cam 36 is rotated clockwise (FIG.-2). Progressive steps in the rotation of the cam 36 are illustrated in FIGS. 3, 4, and 5. During rotation of the cam 36 between the position shown in FIG. 2 and the position shown in FIG. 3, the camming slot 42 cooperates with the pin 40 to withdraw the locking pin 28 from the pin receiving member 30. By this means, rotation of the blade 24 about the axis of the pin 24 is permitted.

Immediately following disengagement of the locking pin 28 from the pin receiving member 30, the cam 36 engages the stop 46 on the fitting 22. Continued clockwise rotation of the cam 36 under the action of the rotary actuator 32 causes pivotal movement of the blade 24 from the extended position shown in FIGS. 1, 2, and 3 through the position shown in FIG. 4 to the folded position shown in FIG. 5. As has been indicated, the cams 58, the cam followers 56, and the cam follower receiving portion 54 of the pawl 50 are responsive to rotation of the blade 24 out of the extended position to lock the pawl 50 in engagement with the surface 48 of the cam 36.

Clockwise rotation of the cam 36 is terminated upon actuation ofa limit switch (not shown) which functions to disable the drive motor of the rotary actuator 32. The limit switch also actuates the brake of the rotary actuator 32, which operates through the speed reducer 34, the pin 18, and the cams 36 to retain the blade 24 in the folded position shown in FIG. 5.

Whenever it is desired to return the blade 24 from the folded position to the extended position, the rotary actuator 32 is operated to rotate the cam 36 counterclockwise (FIG. 5). Since the pawl 50 is locked into engagement with the surface 48 of the cam 36 by the cooperation of the cams 58, the cam followers 56, and the cam follower receiving portion 54 of the pawl 50, the cam 36 operates during counterclockwise rotation to pivot the blade 24 from the position shown in FIG. 5 through the position shown in FIG. 4 to the position shown in FIG. 3. Counterclockwise rotation of the fitting 22 and the blade 24 is terminated by engagement of the fitting 22 with a stop 64 attached to the grip 12.

When the blade 24 is in the position shown in FIG. 3, the cam followers 56 are positioned as shown in FIG. 1, i.e., out of alignment with the cams 58. This permits disengagement of the pawl 50 from the surface 48 of the cam 36. Upon further counterclockwise rotation of the cam 36, the camming slot 42 cooperates with the pin 40 to slide the locking pin 28 into the pin receiving member 30. By this means, the component parts of the powered folding mechanism are returned to the positions shown in FIGS. 1 and 2. A limit switch (not shown) is provided for disabling the drive motor of the rotary actuator 32 as soon as the locking pin 28 is fully seated in the pin receiving member 30.

Referring now to FIG. 6, there is showna powered folding mechanism 100 comprising a second embodiment of the invention. The mechanism 100 includes a blade 102, a grip 104, and a drag link 106. The inboard end of the blade 102 is pivotally attached to the outboard end of the grip 104 by a pivot pin 108. The grip 104 is supported on a hub 110 which is in turn supported on a mast 112. It will be understood that in actual practice the hub l 10 supports additional grips 104 and blades 120 which are constructed substantially as shown in FIG. 6.

The apparatus shown in FIG. 6 comprises a portion of a convertiplane. In the use of such a device, the mast 112 is initially oriented vertically and the hub l 10 is actuated to pivot the various grips 104 so that the planes of the blades 102 extend perpendicularly to the axis of the mast 1 12. Thereafter, the mast 112, the hub 110, the grips 104, and the blades 102 of the aircraft are rotated to provide lift.

After the convertiplane is airborned, separate mechanisms are actuated for horizontal flight. Then, the mast 112 is tilted into a horizontal orientation and the hub is actuated to feather the blades 102, that is, to rotate the grips 104 90 so that the planes of the blades 102 extend parallel to the axis of the mast 112. By this means, the drag imposed by the convertiplane during horizontal flight is substantially reduced. Finally, powered folding mechanisms of the type shown in FIG. 6 are actuated to fold the blades, whereby the drag imposed on the convertiplane during horizontal flight is reduced still further.

The drag link 106 of the powered folding mechanism 100 includes a first arm 114 which issupported on the grip 104 for rotation about an axis 116. The arm 114 extends to an inner member 118 of a pivot connection 120. The drag link 106 further includes a second arm 122 which is supported on the blade 102 for rotation about an axis 124. The arm 122 extends to an outer member 126 of the pivot connection 120.

The outer member 126 of the pivot connection has a pin receiving notch 128 formed in it. A locking pin 130 is slidably supported on the arm 114, and is normally received in the notch 128 to lock the drag link 106 in the position shown in FIG. 6 wherein the arm 122 extends parallel to the arm 1 14. By this means, the blade 102 is locked in the extended position shown in FIG. 6.

The powered folding mechanism 100 further includes a cam 132 which is supported on the grip 104 for rotation about the axis 116. The cam 132 extends to a pin 134 which is received in a camming slot 136 formed in the locking pin 130. Upon initial rotation of the cam 132 clockwise (FIG. 6) about the axis 1 16, the pin 134 and the slot 136 cooperate to withdraw the locking pin 130 from a notch 128. Thereafter, the cam 132 pivots the arm 114 clockwise (FIG. 6) about the axis 116. By this means, the drag link 106 is buckled about the pivot connection 120. This action in turn pivots the blade 102 about the axis of the pivot pin 108 until the blade 102 is in a folded position relative to the grip 104.

It would be possible to operate the cam 132 by means of a rotary actuator similar to the rotary actuator 32 shown in FIG. 1. However, in the apparatus shown in FIG. 6, the cam 132 is connected to the output of a worm gear speed reducer 138. The speed reducer 138 is in turn driven from a grip lockout gear box 140 which is coupled to the speed reducer 138 through a pair of right angled drive mechanisms 142 and 144 and a flexible shaft 146.

When the blade 102 and the grip 104 are oriented in the feathered position shown in FIG. 6, the grip lockout gear box engages a hub gear box 148. A gear is connected to the input of the gear box 148 and is mounted in mesh with a ring gear 152. The ring gear 152 is driven by a plurality of hydraulic motors (not shown) to supply operating power for the cam 132 of the powered folding mechanism 100 individual to each blade of the convertiplane.

It will be understood that the gear box 140 is only in alignment with the gear box 148 when the blade 102 is oriented relative to the mast 112 in the manner shown in FIG. 6. The gear boxes 140 and 148 are arranged to form a drive connection between the ring gear 152 and the cams 132 individual to the various blades of the convertiplane when the blades are feathered and thus properly oriented for folding. On the other hand, whenever a particular blade 102 is oriented otherwise than in the feathered position, the gear box 140 locksthe cam 132 associated with that blade against rotation. By this means, each blade of the convertiplane is prevented from movement to the folded position except when it is feathered.

The operation of the powered folding mechanism 100 will be better understood by referring to FIGS. 7, 8, and 9. Upon initial rotation of the cam 132, the pin 134 connected to the cam 132 and the camming slot 136 formed in the locking pin 130 cooperate to withdraw the locking pin 130 from the notch 128. By this means, the drag link 106 is unlatched and is enabled for buckling movement about the pivot connection 120. Upon further rotation of the cam 132, the drag link 106 is buckled, that is, the arms 114 and 122 are pivoted relative to each other from the orientation shown in FIG. 7 through the orientation shown in FIG. 8 to the orientation shown in FIG. 9. Because the arms 114 and 122 are pivotally connected to the grip 104 and to the blade 102, respectively, this action pivots the blade 102 relative to the grip 104 from the extended position shown in FIG. 7 through the position shown in FIG. 8 to the folded position shown in FIG. 9.

The blade 102 is returned to the extended position shown in FIG. 6 by rotating the cam 132 counterclockwise (FIG. 9). This action first returns the drag link from the buckled condition shown in FIG. 9 to the condition shown in FIG. 7 wherein the arms 114 and 122 of the drag link 106 extend parallel to one another. Also, because the arms 114 and 122 are pivotally connected to the grip 104 and to the blade 102, this action returns the blade 102 to the extended condition shown in FIG. 6. Rotation of the arm 114 due to rotation of the cam 132 is terminated upon engagement of the arm 114 with a stop 154 mounted on the grip 104.

Upon further counterclockwise rotation of the cam 132, the pin 134 and the slot 136 cooperate to slide the locking pin 130 relative to the arm 114 and into engagement with the pin receiving notch 128. By this means, the arms 114 and 122 of the drag link 106 are locked in the position shown in FIG. 6 and the blade 102 is thereby prevented from pivotal movement relative to the grip 104.

Those skilled in the art will realize that whereas in the apparatus shown in the Drawings, the folding mechanisms 10 and 100 are employed to fold the blades of rotary wing aircraft, both of the embodiments of the invention are readily adaptable to non-aircraft usages. For example, the present invention may be employed in door opening or closing mechanisms, various jacking and/or lifting apparatus, and in many other devices.

From the foregoing, it will be understood that the present invention comprises a powered folding mechanism including a first member, a second member pivotally supported on the first member, a locking member supported on the second member, structure on the first member for receiving the locking member to retain the second member in a first position relative to the first member, and camming means for operation in one direction to first disengage the locking member and then pivot the second member relative to the first member and for operation in the opposite direction to first return the second member to its original position and then re-engage the locking member. The use of the invention is advantageous in that a single actuator is operable to first unlock a second member from a first member and then to pivot the second member relative to the first member. Another advantageous feature of the invention is that the second member is positively locked in one of its positions and is thus completely prevented from pivotal movement relative to the first member.

Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of rearrangement, modification, and substitution of parts and elements without departing from the spirit of the invention.

What is claimed is:

1. In a rotary wing aircraft, a blade folding nism comprising:

an inboard blade grip;

an outboard blade;

means interconnecting the outboard end of the grip and the inboard end of the blade and supporting the blade for pivotal movement relative to the grip about a predetermined axis;

a locking pin supported for pivotal movement with the blade and for sliding movement with respect thereto;

means mounted on the grip for normally receiving the locking pin and thereby retaining the blade in an extended positionv relative to the grip;'and

. camming means mounted on the grip for rotation in one direction about said predetermined axis to first disengage the locking pin from the pin receiving means and then to pivot the blade about said axis to a folded position relative to the grip and thereafter for rotation in the opposite direction about said axis to first pivot the blade about said axis to the extended position relative to the grip and then to engage the locking pin withthe locking pin receiving means to retain the blade in the extended position.

2. The blade folding mechanism according to claim 1 wherein the camming means further includes pin and slot means interconnecting the locking pin and the camming means and responsive to rotation of the cam for sliding the locking pin in and out of engagement with the pin receiving means.

3. The blade folding mechanism according to claim 2 further including a latching surface formed on the camming means, a pawl attached to the blade for rotation therewith, and means responsive to rotation of the blade away from the extended position for latching the pawl into engagement with the latching surface on the camming means 4. The blade folding mechanism according to claim 3 wherein the pawl latching means comprises a cam mounted on the blade grip, a cam followersupported for rotation with the blade and positioned for engagement with the cam on the grip in response to rotation mechaof the blade away from the extended position, and cooperating surfaces on the cam follower and the pawl for retaining the pawl in engagement with the latching surface whenever the cam follower is engaged with the cam on the grip.

5. Apparatus for folding a blade of a rotary wing aircraft which comprises:

a blade grip;

a blade supported on the blade grip for pivotal movement about a predetermined axis;

a latching pin supported on the blade for reciprocation with respect thereto and for pivotal movement with the blade relative to the grip;

means mounted on the grip for normally receiving the latching pin and thereby securing the blade in an extended position relative to the grip; and

a member supported for rotation in one direction about said predetermined axis first relative both to the blade and to the grip to disengage the locking pin from the receiving means and then for engagement and rotation with the blade relative to the grip to pivot the blade to a folded position relative to the grip and for rotation in the opposite direction about said predetermined axis first with the blade relative to the grip to return the blade to the extended position and then relative to the blade and the grip to engage the locking pin with the re taining means.

6. The blade folding apparatus according to claim further characterized by:

means for latching the blade to the rotating member and thereby assuring pivotal movement of the blade to the extended position upon rotation of the member in said opposite direction about said predetermined axis; and

means responsive to pivotal movement of the blade out of the extended position relative to the grip for actuating the latching means.

7. The blade folding apparatus according to claim 6 wherein the latching means comprises a latching surface on the rotating member and a cooperating latching member mounted on the blade and wherein the actuating means comprises cooperating camming means on the blade and on the grip for securing the latching member in engagement with the latching surface whenever the blade is pivoted out of the extended position relative to the grip.

8. The blade folding apparatus according to claim 5 wherein the latching pin is connected to the rotating member by pin and slot means responsive to rotation of the member in one direction relative to the grip and the blade to disengage the latching pin from the latching pin receiving means and responsive to rotation of the member in an opposite direction relative to the blade and the grip to engage the latching pin with the latching pin receiving means.

9. The blade folding apparatus according to claim 5 wherein the outboard end of the grip and the inboard end of the blade comprise bifurcated portions which are interleaved at said predetermined axis and defining an open space therebetween, and wherein the rotating member is positioned within the open space between the bifurcations of the blade and the grip. 

1. In a rotary wing aircraft, a blade folding mechanism comprising: an inboard blade grip; an outboard blade; means interconnecting the outboard end of the grip and the inboard end of the blade and supporting the blade for pivotal movement relative to the grip about a predetermined axis; a locking pin supported for pivotal movement with the blade and for sliding movement with respect thereto; means mounted on the grip for noRmally receiving the locking pin and thereby retaining the blade in an extended position relative to the grip; and camming means mounted on the grip for rotation in one direction about said predetermined axis to first disengage the locking pin from the pin receiving means and then to pivot the blade about said axis to a folded position relative to the grip and thereafter for rotation in the opposite direction about said axis to first pivot the blade about said axis to the extended position relative to the grip and then to engage the locking pin with the locking pin receiving means to retain the blade in the extended position.
 2. The blade folding mechanism according to claim 1 wherein the camming means further includes pin and slot means interconnecting the locking pin and the camming means and responsive to rotation of the cam for sliding the locking pin in and out of engagement with the pin receiving means.
 3. The blade folding mechanism according to claim 2 further including a latching surface formed on the camming means, a pawl attached to the blade for rotation therewith, and means responsive to rotation of the blade away from the extended position for latching the pawl into engagement with the latching surface on the camming means
 4. The blade folding mechanism according to claim 3 wherein the pawl latching means comprises a cam mounted on the blade grip, a cam follower supported for rotation with the blade and positioned for engagement with the cam on the grip in response to rotation of the blade away from the extended position, and cooperating surfaces on the cam follower and the pawl for retaining the pawl in engagement with the latching surface whenever the cam follower is engaged with the cam on the grip.
 5. Apparatus for folding a blade of a rotary wing aircraft which comprises: a blade grip; a blade supported on the blade grip for pivotal movement about a predetermined axis; a latching pin supported on the blade for reciprocation with respect thereto and for pivotal movement with the blade relative to the grip; means mounted on the grip for normally receiving the latching pin and thereby securing the blade in an extended position relative to the grip; and a member supported for rotation in one direction about said predetermined axis first relative both to the blade and to the grip to disengage the locking pin from the receiving means and then for engagement and rotation with the blade relative to the grip to pivot the blade to a folded position relative to the grip and for rotation in the opposite direction about said predetermined axis first with the blade relative to the grip to return the blade to the extended position and then relative to the blade and the grip to engage the locking pin with the retaining means.
 6. The blade folding apparatus according to claim 5 further characterized by: means for latching the blade to the rotating member and thereby assuring pivotal movement of the blade to the extended position upon rotation of the member in said opposite direction about said predetermined axis; and means responsive to pivotal movement of the blade out of the extended position relative to the grip for actuating the latching means.
 7. The blade folding apparatus according to claim 6 wherein the latching means comprises a latching surface on the rotating member and a cooperating latching member mounted on the blade and wherein the actuating means comprises cooperating camming means on the blade and on the grip for securing the latching member in engagement with the latching surface whenever the blade is pivoted out of the extended position relative to the grip.
 8. The blade folding apparatus according to claim 5 wherein the latching pin is connected to the rotating member by pin and slot means responsive to rotation of the member in one direction relative to the grip and the blade to disengage the latching pin from the latching pin receiving means and responsive to rotation of the member in an opposite direction relative to the blade and the grip to engage the latching pin with the latching pin receiving means.
 9. The blade folding apparatus according to claim 5 wherein the outboard end of the grip and the inboard end of the blade comprise bifurcated portions which are interleaved at said predetermined axis and defining an open space therebetween, and wherein the rotating member is positioned within the open space between the bifurcations of the blade and the grip. 